Various processes have been developed to apply coatings to glass containers for different purposes, including glass strengthening for damage prevention and fragment retention. For example, U.S. Pat. No. 3,522,075 discloses a process for coating a glass container in which the glass container is formed, coated with a layer of metal oxide such as tin oxide, cooled through a lehr, and then coated with an organopolysiloxane resin-based material over the metal oxide layer. In another example, U.S. Pat. No. 3,853,673 discloses a method of strengthening a glass article by, for example, applying to a surface of the article a clear solution of a soluble, further hydrolyzable metallosiloxane, and maintaining the glass article at an elevated temperature sufficiently high to convert the metallosiloxane to a cross-linked polymetallosiloxane gel structure. In a further example, U.S. Pat. No. 3,912,100 discloses a method of making a glass container by heating the glass container and applying a polyurethane powder spray to the glass container.
A general object of the present disclosure, in accordance with one aspect of the disclosure, is to provide an improved method of increasing strength and/or fragment retention of a glass container.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A method of coating an exterior surface of a glass container in accordance with one aspect of the disclosure includes the steps of (a) providing a heated hybrid sol-gel having a composition including at least one silane and at least one solvent, (b) coating the exterior glass surface of the glass container with the heated hybrid sol-gel, and (c) heating the coated exterior glass surface of the glass container to cross-link the hybrid sol-gel and result in a coating on the exterior glass surface of the glass container having greater than 90% silicate-based material by weight.
In accordance with a further aspect of the disclosure, there is provided a glass container that includes an axially closed base at an axial end of the glass container, a body extending axially from the base and being circumferentially closed, an axially open mouth at another end of the glass container opposite of the base, and an exterior glass surface. The glass container also includes a hybrid sol-gel cross-linked on at least a portion of the exterior glass surface.
In accordance with an additional aspect of the disclosure, there is provided a glass container that includes an axially closed base at an axial end of the glass container, a body extending axially from the base and being circumferentially closed, an axially open mouth at another end of the glass container opposite of the base, and an exterior glass surface. The glass container also includes a coating of hybrid sol-gel on at least a portion of the exterior glass surface, wherein the hybrid sol-gel includes at least one silane and at least one solvent.
In accordance with another aspect of the disclosure, there is provided a method of manufacturing a glass container including the steps of forming the glass container, applying a hot end coating to an exterior glass surface of the glass container, and annealing the glass container. The method also includes heating a hybrid sol-gel to a temperature of between 70 degrees Celsius and 130 degrees Celsius, wherein a composition of the hybrid sol-gel includes 50% to 60% by weight of at least one silane and 40% to 50% by weight of at least one solvent wherein the heated hybrid sol-gel has a viscosity of between 0.001 Pa-s and 100 Pa-s, coating the exterior glass surface of the glass container with the heated hybrid sol-gel, at a temperature between 80 degrees Celsius and 140 degrees Celsius, and heating the coated exterior glass surface of the glass container at a temperature between 140 degrees Celsius and 160 degrees Celsius for a time between ten minutes and ten hours to cross-link the hybrid sol-gel and result in a coating on the exterior glass surface of the glass container having greater than 90% silicate-based material by weight to increase at least one of strength or fragment retention of the glass container. The method further includes applying a cold end coating to the exterior glass surface of the glass container.